/Engine/Source/Developer/MaterialUtilities/Public/MaterialUtilities.h
Calculates an importance value for the given set of materials according to the texture sampler usage
static void DetermineMaterialImportance ( const [TArray](API\Runtime\Core\Containers\TArray)< [UMaterialInterface](API\Runtime\Engine\Materials\UMaterialInterface) * > & InMaterials, [TArray](API\Runtime\Core\Containers\TArray)< float > & OutImportance )